__traits so long and ugly, what about ::?

[Jacob Carlborg]

On 2011-03-31 01:05, KennyTM~ wrote:
> On Mar 31, 11 06:32, Ary Manzana wrote:
>> On 3/30/11 5:52 PM, KennyTM~ wrote:
>>> On Mar 31, 11 04:19, Alix Pexton wrote:
>>>> On 30/03/2011 20:45, KennyTM~ wrote:
>>>>> This is confusing as :: is used to separate scopes in C++ (and PHP
>>>>> too).
>>>>
>>>> The first thing it reminded me of was Lua, where a single colon makes
>>>> the left hand side into the first argument of the function on the
>>>> right.
>>>>
>>>> foo:bar(x) ==> bar.(foo, x)
>>>>
>>>> So it felt kinda familiar to me ^^
>>>>
>>>> A...
>>>
>>> That is almost like UFCS in D.
>>>
>>> int foo(string x, int y) { return x.length - y; }
>>>
>>> assert (foo("testing", 3) == 4);
>>> assert ("testing".foo(3) == 4);
>>>
>>> But OP's proposal is restricted to __traits only.
>>>
>>> __traits is a relatively advanced part of the language, plus many of its
>>> features has already been exposed via the library std.traits, e.g.
>>> std.traits.hasMember!(S, "m"), I don't think it really needs a very
>>> short syntax.
>>
>> Look, metaprogramming in Ruby is a relatively advanced part of the
>> language. And you know why it is heavily used and everyone can jump and
>> start using it in a matter of seconds and build the most amazing things?
>> Because it's very, very, very, (add 1000 very words here), very easy to
>> use.
>>
>
> We're talking about __traits, a feature for compile-time reflection
> where most of its capability is already wrapped up to std.traits. It
> isn't comparable with the whole metaprogramming capability in another
> language.
>
> You know, metaprogramming is also heavily used in D, because of a
> sensible template system, mixins and CTFE, not __traits.
>
>> Why make *anything* hard to use if you can do it in an easier way?
>
> Is
>
> meta.hasMember(S, "m")
>
> or even
>
> import std.traits;
> ...
> hasMember!(S, "m")
>
> really that hard to use?
>
> I think the 'meta' namespace is enough. 'A::B' is too much for such a
> low-level feature.

In Ruby it would just be: S.hasMember("m") and "hasMember" would just be 
a regular plain old method, nothing special about it.

-- 
/Jacob Carlborg